A process control system may include a digital data processor that includes actuators for controlling a process, and a graphical display device for displaying process-related information to an operator. The system may also include one or more operator input devices for receiving input from the operator of the system. The display may graphically illustrate a current state of the process being controlled, and may also provide a list of one or more state variables for control by the operator. Examples include, but are not limited to, an environmental control system for a large building, a control system for a pharmaceutical manufacturing process, a petrochemical refining process, a control system for an automated manufacturing operation, and a control system for imaging or photographic devices.
In general, in known types of systems the operator is restricted to attempting to reach an alternate state by trial and error manipulation of some system variables. By example, in an environmental control system the operator may be enabled to vary the hot air flow to a selected zone of a building. However, the use of trial and error methods may not always provide an optimum environmental solution.
Furthermore, the use of preprogrammed, or accessed, next system states may not always provide an optimum solution to a particular process control problem.
For either the trial and error approach, or the preprogrammed approach, the operator may not be sufficiently aware of a consequence of a particular next state upon the controlled system so as to make an informed decision as to an appropriate next state, based on a current state of the system.
Known systems typically provide graphical representations of objects, and provide means for implementing "controls" on these objects to obtain a desired behavior. As an example, in U.S. Pat. No. 4,649,499, issued Mar. 10, 1987, entitled "Touchscreen Two-Dimensional Emulation of Three-Dimensional Objects" J. Sutton et al described the use of a touchscreen to emulate three-dimensional objects on a two-dimensional computer screen. The system is employed to emulate the operation of a desktop rotary card file and a hand held calculator. In the calculator embodiment an image of a calculator is displayed and an operator touches the displayed "keys" to operate the calculator. What is not disclosed is the generation and display of derived (potential) next states of a process, in conjunction with a current state of the process, or the ability to enable a user to select one of a plurality of derived next states to become a next current state.
It is thus an object of this invention to provide a process control system user interface that derives one or more next states of a system based upon a current state of the system and upon a computational model of the system, and which furthermore provides a visual display of the one or more derived next states in conjunction with a visual display of the current state.
It is a further object of this invention to provide a process control system user interface that derives one or more next states of a system based upon a current state of the system and upon a computational model of the system, which provides a visual display of the one or more derived next states and a visual display of the current state, and which drives the system to a next state in response to the operator selecting one of the one or more displayed derived next states.